Home-based Circuit Training and Community Walking for Intermittent Claudication.

BACKGROUND: Supervised exercise training is recommended for people with peripheral artery disease (PAD), yet it remains underutilized. Home-based exercise programs (HBEPs) are a potential alternative. The aim of this study was to assess the feasibility of conducting a full scale trial of a 12-week HBEP for people living with symptomatic PAD. METHODS: In a randomized feasibility trial, patients with intermittent claudication were allocated to either an HBEP or a nonexercise control. The HBEP group was given a Fitbit to use during a 12-week exercise program comprising of personalized step goals and a resistance-based circuit to be undertaken at home twice weekly. The primary outcome was feasibility, assessed via eligibility, recruitment, attrition, tolerability, and adherence. Acceptability was assessed via semistructured interviews. Secondary analysis was undertaken to determine the feasibility of collecting clinical outcome data. RESULTS: 188 people were screened, 133 were eligible (70.7%), 30 were recruited (22.6%) and one withdrew (3.33%). Mean adherence to the daily step goal was 53.5% (range = 29.8-90.5%), and 58.6% of prescribed circuits were completed of which 56.4% were at the desired intensity. Six adverse events were recorded, 3 of which were related to study involvement. No significant differences were observed in exploratory outcomes. Small clinically important differences were seen in walking speed and pain-free treadmill walking distance which should be confirmed or refuted in a larger trial. CONCLUSIONS: The HBEP was feasible and well tolerated, with successful recruitment and minimal attrition. The intervention was acceptable, with walking seen as more enjoyable than circuit exercise. The WALKSTRONG program may be suitable for those who will not, or cannot, take part in supervised exercise outside of the home.

Inter- and intra-observer reliability and agreement of O2Pulse inflection during cardiopulmonary exercise testing: A comparison of subjective and novel objective methodology.

Cardiopulmonary exercise testing (CPET) is the 'gold standard' method for evaluating functional capacity, with oxygen pulse (O2Pulse) inflections serving as a potential indicator of myocardial ischaemia. However, the reliability and agreement of identifying these inflections have not been thoroughly investigated. This study aimed to assess the inter- and intra-observer reliability and agreement of a subjective quantification method for identifying O2Pulse inflections during CPET, and to propose a more robust and objective novel algorithm as an alternative methodology. A retrospective analysis was conducted using baseline data from the HIIT or MISS UK trial. The O2Pulse curves were visually inspected by two independent examiners, and compared against an objective algorithm. Fleiss' Kappa was used to determine the reliability of agreement between the three groups of observations. The results showed almost perfect agreement between the algorithm and both examiners, with a Fleiss' Kappa statistic of 0.89. The algorithm also demonstrated excellent inter-rater reliability (ICC) when compared to both examiners (0.92-0.98). However, a significant level (P ≤0.05) of systematic bias was observed in Bland-Altman analysis for comparisons involving the novice examiner. In conclusion, this study provides evidence for the reliability of both subjective and novel objective methods for identifying inflections in O2Pulse during CPET. These findings suggest that further research into the clinical significance of O2Pulse inflections is warranted, and that the adoption of a novel objective means of quantification may be preferable to ensure equality of outcome for patients.

Effects of Exercise Training Response on Quality of Life and Cardiovascular Risk Factor Profiles in People With Coronary Artery Disease: Insights From the HIIT or MISS UK Trial.

OBJECTIVE: To compare the characteristics of responders and nonresponders to 8 weeks of exercise training to determine differences in key cardiovascular disease outcomes in people with coronary artery disease (CAD). DESIGN: Secondary analysis of data from the HIIT or MISS UK trial. SETTING: Six outpatient National Health Service cardiac rehabilitation (CR) centers in the UK. In people with CAD attending CR, the HIIT or MISS UK trial reported that short-term, low-volume, high-intensity interval training (HIIT) was more effective than moderate-intensity steady state (MISS) exercise training for improving peak oxygen uptake (V̇o2peak). PARTICIPANTS: 382 participants with CAD (N=382) (mean age: 58.8±9.6y; mean body mass index: 29.0±4.3 kg/m2). MAIN OUTCOME MEASURES: We identified responders and nonresponders based on a meaningful change in V̇o2peak, using 2 established methods. Key clinical, quality of life (QoL), and cardiopulmonary exercise test (CPET)-derived outcomes were compared between groups. RESULTS: Responders were more likely to be younger (P<.05), and demonstrate greater improvement in CPET-related outcomes, for example, oxygen uptake efficiency slope, ventilatory efficiency, and peak power output (all comparisons, P<.001). Responders were more likely to observe improvements in QoL (EQ-5D-5L; mean Δ 13.6 vs mean Δ 9.4; P=.045), and high-density lipoprotein cholesterol (HDL-c) (mean Δ 0.09 mmol/L vs mean Δ 0.04 mmol/L; P=.004), compared to nonresponders. CONCLUSIONS: In people with CAD attending CR, responders to exercise training were more likely to be younger and demonstrate greater improvements in health-related QoL and HDL-c.

Mobile health biometrics to prescribe immediate remote physical activity for enhancing uptake to cardiac rehabilitation (MOTIVATE-CR+): protocol for a randomised controlled feasibility trial.

INTRODUCTION: Cardiac rehabilitation (CR) can reduce cardiovascular mortality and improve health-related quality of life. In the United Kingdom, patient uptake of CR remains low (52%), falling well short of the target in the 2019 National Health Service long-term plan (85%). Mobile health (mHealth) technologies, offering biometric data to patients and healthcare professionals, may bridge the gap between supervised exercise and physical activity advice, enabling patients to engage in regular long-term physically active lifestyles. This randomised controlled trial (RCT) will evaluate the feasibility of mHealth technology when incorporated into a structured home-based walking intervention, in people with recent myocardial infarction. METHODS AND ANALYSIS: This is a feasibility, assessor blinded, parallel group RCT. Participants will be allocated to either CR standard care (control group) or CR standard care+mHealth supported exercise counselling (mHealth intervention group). Feasibility outcomes will include the number of patients approached, screened and eligible; the percentage of patients who decline CR (including reasons for declining), agree to CR and consent to being part of the study; the percentage of patients who enrol in standard CR and reasons for drop out; and the percentage of participants who complete clinical, physical and psychosocial outcomes to identify a suitable primary outcome for a future definitive trial. ETHICS AND DISSEMINATION: The trial was approved in the UK by the Northwest-Greater Manchester East Research Ethics Committee (22/NW/0301) and is being conducted in accordance with the Declaration of Helsinki and Good Clinical Practice. Results will be published in peer-reviewed journals and presented at national and international scientific meetings. TRIAL REGISTRATION NUMBERS: NCT05774587.

Clinical effectiveness of an online supervised group physical and mental health rehabilitation programme for adults with post-covid-19 condition (REGAIN study): multicentre randomised controlled trial.

OBJECTIVE: To evaluate whether a structured online supervised group physical and mental health rehabilitation programme can improve health related quality of life compared with usual care in adults with post-covid-19 condition (long covid). DESIGN: Pragmatic, multicentre, parallel group, superiority randomised controlled trial. SETTING: England and Wales, with home based interventions delivered remotely online from a single trial hub. PARTICIPANTS: 585 adults (26-86 years) discharged from NHS hospitals at least three months previously after covid-19 and with ongoing physical and/or mental health sequelae (post-covid-19 condition), randomised (1:1.03) to receive the Rehabilitation Exercise and psycholoGical support After covid-19 InfectioN (REGAIN) intervention (n=298) or usual care (n=287). INTERVENTIONS: Best practice usual care was a single online session of advice and support with a trained practitioner. The REGAIN intervention was delivered online over eight weeks and consisted of weekly home based, live, supervised, group exercise and psychological support sessions. MAIN OUTCOME MEASURES: The primary outcome was health related quality of life using the patient reported outcomes measurement information system (PROMIS) preference (PROPr) score at three months. Secondary outcomes, measured at three, six, and 12 months, included PROMIS subscores (depression, fatigue, sleep disturbance, pain interference, physical function, social roles/activities, and cognitive function), severity of post-traumatic stress disorder, general health, and adverse events. RESULTS: Between January 2021 and July 2022, 39 697 people were invited to take part in the study and 725 were contacted and eligible. 585 participants were randomised. Mean age was 56 (standard deviation (SD) 12) years, 52% were female participants, mean health related quality of life PROMIS-PROPr score was 0.20 (SD 0.17), and mean time from hospital discharge was 323 (SD 144) days. Compared with usual care, the REGAIN intervention led to improvements in health related quality of life (adjusted mean difference in PROPr score 0.03 (95% confidence interval 0.01 to 0.05), P=0.02) at three months, driven predominantly by greater improvements in the PROMIS subscores for depression (1.39 (0.06 to 2.71), P=0.04), fatigue (2.50 (1.19 to 3.81), P<0.001), and pain interference (1.80 (0.50 to 3.11), P=0.01). Effects were sustained at 12 months (0.03 (0.01 to 0.06), P=0.02). Of 21 serious adverse events, only one was possibly related to the REGAIN intervention. In the intervention group, 141 (47%) participants fully adhered to the programme, 117 (39%) partially adhered, and 40 (13%) did not receive the intervention. CONCLUSIONS: In adults with post-covid-19 condition, an online, home based, supervised, group physical and mental health rehabilitation programme was clinically effective at improving health related quality of life at three and 12 months compared with usual care. TRIAL REGISTRATION: ISRCTN registry ISRCTN11466448.

Validating the Fitbit Charge 4© wearable activity monitor for use in physical activity interventions.

OBJECTIVES: Commercially available wearable activity monitors can promote physical activity behaviour. Clinical trials typically quantify physical activity with research grade activity monitors prior to testing interventions utilising commercially available wearable activity monitors aimed at increasing step count. Therefore, it is important to test the agreement of these two types of activity monitors. OBJECTIVES: Observational. METHODS: Thirty adults (20-65 years, n = 19 females) were provided a Fitbit Charge 4©. To determine reliability using an intraclass correlation coefficient, two, one-minute bouts of treadmill walking were performed at a self-selected pace. Subsequently, participants wore both an ActiGraph wGT3X-BT and the Fitbit for seven days. To determine agreement, statistical equivalence and the mean absolute percentage error were calculated and represented graphically with a Bland-Altman plot. Ordinary least products regression was performed to identify fixed or proportional bias. RESULTS: The Fitbit showed 'good' step count reliability on the treadmill (intraclass correlation coefficient = 0.75, 95 % CI = 0.53-0.87, p < 0.001). In free-living however, it overestimated step count when compared to the ActiGraph wGT3X-BT (mean absolute percentage error = 26.02 % ±â€¯14.63). Measurements did not fall within the ± 10 % equivalence region and proportional bias was apparent (slope 95 % CI = 1.09-1.35). CONCLUSIONS: The Fitbit Charge 4© is reliable when measuring step count on a treadmill. However, there is an overestimation of daily steps in free-living environments which may falsely indicate compliance with physical activity recommendations.

High INtensity Interval Training in pATiEnts with Intermittent Claudication: A Qualitative Acceptability Study.

BACKGROUND: A novel high-intensity interval training (HIIT) program has demonstrated feasibility for patients with intermittent claudication (IC). The aim of this study was to explore patient perspectives of the HIIT program to inform refinement and future research. METHODS: All patients screened and eligible for the 'high intensity interval training in patients with intermittent claudication (INITIATE)' study were eligible to take part in a semistructured interview. A convenience subsample of patients was selected from 3 distinct groups: 1) those who completed the HIIT program, 2) those who prematurely discontinued the HIIT program, and 3) those who declined the HIIT program. Interviews considered patients views of the program and experiences of undertaking and/or being invited to undertake it. Interviews were audio recorded, transcribed verbatim, and analyzed via thematic analysis. RESULTS: Eleven out of 31 participants who completed the program and 12 out of 38 decliners were interviewed. No participants who withdrew from the program agreed to interview. The 3 key themes were; personal reflections of the program; program facilitators and barriers; and perceived benefits. Completers enjoyed taking part, reported symptomatic improvement and would complete it again. Practical and psychological barriers exist, such as transport and motivation. Changes to the program were suggested. CONCLUSIONS: Findings support the acceptability of this novel HIIT program, which in combination with the feasibility findings, suggest that a fully powered randomized controlled trial, comparing HIIT to usual-care supervised exercise programs is warranted.

Cost-effectiveness of High-Intensity Interval Training (HIIT) vs Moderate Intensity Steady-State (MISS) Training in UK Cardiac Rehabilitation.

OBJECTIVE: To perform a cost-effectiveness analysis of high-intensity interval training (HIIT) compared with moderate intensity steady-state (MISS) training in people with coronary artery disease (CAD) attending cardiac rehabilitation (CR). DESIGN: Secondary cost-effectiveness analysis of a prospective, assessor-blind, parallel group, multi-center RCT. SETTING: Six outpatient National Health Service cardiac rehabilitation centers in England and Wales, UK. PARTICIPANTS: 382 participants with CAD (N=382). INTERVENTIONS: Participants were randomized to twice-weekly usual care (n=195) or HIIT (n=187) for 8 weeks. Usual care was moderate intensity continuous exercise (60%-80% maximum capacity, MISS), while HIIT consisted of 10 × 1-minute intervals of vigorous exercise (>85% maximum capacity) interspersed with 1-minute periods of recovery. MAIN OUTCOME MEASURES: We conducted a cost-effectiveness analysis of the HIIT or MISS UK trial. Health related quality of life was measured with the EQ-5D-5L to estimate quality-adjusted life years (QALYs). Costs were estimated with health service resource use and intervention delivery costs. Cost-utility analysis measured the incremental cost-effectiveness ratio (ICER). Bootstrapping assessed the probability of HIIT being cost-effective according to the UK National Institute for Health and Care Excellence (NICE) threshold value (£20,000 per QALY). Missing data were imputed. Uncertainty was estimated using probabilistic sensitivity analysis. Assumptions were tested using univariate/1-way sensitivity analysis. RESULTS: 124 (HIIT, n=59; MISS, n=65) participants completed questionnaires at baseline, 8 weeks, and 12 months. Mean combined health care use and delivery cost was £676 per participant for HIIT, and £653 for MISS. QALY changes were 0.003 and -0.013, respectively. For complete cases, the ICER was £1448 per QALY for HIIT compared with MISS. At a willingness-to-pay threshold of £20,000 per QALY, the probability of HIIT being cost-effective was 96% (95% CI, 0.90 to 0.95). CONCLUSION: For people with CAD attending CR, HIIT was cost-effective compared with MISS. These findings are important to policy makers, commissioners, and service providers across the health care sector.

Development of an online intervention for the Rehabilitation Exercise and psycholoGical support After covid-19 InfectioN (REGAIN) trial.

Background: Up to half of people hospitalised with COVID-19 report diverse and persistent symptoms affecting quality of life for months and sometimes years after discharge (long-COVID). We describe the development of an online group exercise and behavioural support intervention for people who continue to experience such physical and/or emotional health problems more than three months after hospital discharge. Methods: Intervention development was informed by the Medical Research Council framework for complex interventions. Our multidisciplinary team of academics, clinicians, and people with long-COVID, had collective expertise in the development and testing of complex interventions. We integrated a bio-psycho-social model of care drawing on rehabilitation literature for long-term health conditions and experiences from our pre-pilot study. Multiple stakeholder meetings were held to refine the intervention which was designed to be deliverable within the UK National Health Service. We adhere to TIDieR guidance for transparent and explicit reporting of telehealth interventions. Results: The final REGAIN online exercise and behavioural support intervention consisted of an initial 1:1 consultation with a trained practitioner, followed by eight online group exercise, and six group support, sessions delivered over eight weeks. Participants could also access an online library of on-demand exercise and support videos. Conclusions: The final REGAIN intervention, combining exercise and behavioural support, is fully manualised with clear pathways to delivery and implementation. It is currently being tested in a randomised controlled trial. The intervention, developed with extensive patient and stakeholder engagement, could be incorporated into existing NHS rehabilitation programmes, should it prove to be clinically and cost-effective for people with long-COVID. Trial registration: International Standard Randomised Controlled Trial Number (ISRCTN) 11466448: Rehabilitation exercise and psychological support after COVID-19 infection: REGAIN.

Long-COVID has many debilitating symptoms, such as breathlessness, muscle weakness and fatigue, which significantly affect peoples' physical and mental health and quality of life. Rehabilitation programmes can help people improve their quality of life in other medical conditions with similar symptoms. We developed a programme of physical and mental health rehabilitation, delivered online, specifically to support people with ongoing long-COVID symptoms more than three months after hospital discharge. The programme was developed by people with long-COVID along with clinicians and researchers. The programme described in this article is now being tested in a large research trial to see if it can help people with long-COVID.

Development of a complex exercise rehabilitation intervention for people with pulmonary hypertension: the supervised pulmonary hypertension exercise rehabilitation (SPHERe) trial.

BACKGROUND: People with pulmonary hypertension (PH) are not routinely referred for exercise rehabilitation despite the potential for reducing breathlessness and improving quality of life. We describe the development of a supervised pulmonary hypertension exercise rehabilitation (SPHERe) programme for people with PH. METHODS: Development was completed in three phases: (1) systematic review, (2) stakeholder engagement with consensus from patients and experts and (3) prepilot intervention acceptability testing. We completed systematic reviews to identify international cardiopulmonary rehabilitation guidance and trials of exercise-based interventions for people with PH. Evidence from systematic reviews and stakeholder consensus shaped the SPHERe intervention, including addition of individual behavioural support sessions to promote exercise adherence. The draft SPHERe intervention was ratified through discussions with multidisciplinary professionals and people living with PH. We acceptability tested the centre-based intervention with eight participants in a prepilot development phase which identified a number of condition-specific issues relating to safety and fear avoidance of activity. Comprehensive intervention practitioner training manuals were produced to ensure standardised delivery. Participant workbooks were developed and piloted. Trial recruitment began in January 2020 but was subsequently suspended in March 2020 further to COVID-19 pandemic 'lockdowns'. In response to the pandemic, we undertook further development work to redesign the intervention to be suitable for exclusively home-based online delivery. Recruitment to the revised protocol began in June 2021. DISCUSSION: The final SPHERe intervention incorporated weekly home-based online group exercise and behavioural support 'coaching' sessions supervised by trained practitioners, with a personalised home exercise plan and the optional loan of a stationary exercise bike. The intervention was fully manualised with clear pathways for assessment and individualised exercise prescription. The clinical and cost-effectiveness of the SPHERe online rehabilitation intervention is currently being tested in a UK multicentre randomised controlled trial. TRIAL REGISTRATION NUMBER: ISCRTN10608766.

Co-creation of a complex, multicomponent rehabilitation intervention and feasibility trial protocol for the PostUraL tachycardia Syndrome Exercise (PULSE) study.

BACKGROUND: There is a dearth of research to support the treatment of people with postural tachycardia syndrome (PoTS). Despite expert consensus suggesting exercise is recommended for this patient group, there are no randomised control trials examining this rigorously. The aim was to co-create a feasibility trial protocol and a rehabilitation intervention for people living with PoTS. METHODS: The intervention and feasibility trial design were co-created as part of the PostUraL tachycardia Syndrome Exercise (PULSE) study. We used the 'three co's framework' of co-define, co-design and co-refine. Recruitment included key national charities and National Health Service Trusts treating people living with PoTS in the UK. Eighteen patient and public involvement members attended the co-define session, and 16 co-creators with a mix of expertise attended the subsequent co-design and co-refine sessions. Seven intervention practitioners were trained in the rehabilitation intervention, providing feedback for further co-refinement. RESULTS: The final co-created intervention comprises online physical activity, and lifestyle and behaviour change support sessions. It is based on functional movement activities using a patient-centred approach tailored to individual needs. Physical activity intensity is guided by individuals' perception of effort rather than by objective measures. Recumbent bikes are provided for home use. Patients deemed randomisation to be acceptable because research in this area was considered important. CONCLUSIONS: An innovative approach was used to co-create the PULSE intervention and feasibility trial protocol to meet the evidence-based and logistical needs of people living with PoTS, clinicians, service deliverers, third-sector organisations, academics and funders. This can be used as a successful example and template for future research internationally. People living with PoTS were recognised as experts and involved in every aspect of conceptualisation, design and refinement. This complex rehabilitation intervention is currently being tested in a randomised feasibility trial comparing the PULSE intervention with best-practice usual care for people living with PoTS. TRIAL REGISTRATION: ISRCTN45323485 was registered on April 7, 2020.

Rising arterial stiffness with accumulating comorbidities associates with heart failure with preserved ejection fraction.

AIMS: Comorbidities play a significant role towards the pathophysiology of heart failure with preserved ejection fraction (HFpEF), characterized by abnormal macrovascular function and altered ventricular-vascular coupling. However, our understanding of the role of comorbidities and arterial stiffness in HFpEF remains incomplete. We hypothesized that HFpEF is preceded by a cumulative rise in arterial stiffness as cardiovascular comorbidities accumulate, beyond that associated with ageing. METHODS AND RESULTS: Arterial stiffness was assessed using pulse wave velocity (PWV) in five groups: Group A, healthy volunteers (n = 21); Group B, patients with hypertension (n = 21); Group C, hypertension and diabetes mellitus (n = 20); Group D, HFpEF (n = 21); and Group E, HF with reduced ejection fraction (HFrEF) (n = 11). All patients were aged 70 and above. Mean PWV increased from Groups A to D (PWV 10.2, 12.2, 13.0, and 13.7 m/s, respectively) as vascular comorbidities accumulated independent of age, renal function, haemoglobin, obesity (body mass index), smoking status, and hypercholesterolaemia. HFpEF exhibited the highest PWV and HFrEF displayed near-normal levels (13.7 vs. 10 m/s, P = 0.003). PWV was inversely related to peak oxygen consumption (r = -0.304, P = 0.03) and positively correlated with left ventricular filling pressures (E/e') on echocardiography (r = -0.307, P = 0.014). CONCLUSIONS: This study adds further support to the concept of HFpEF as a disease of the vasculature, underlined by an increasing arterial stiffness that is driven by vascular ageing and accumulating vascular comorbidities, for example, hypertension and diabetes. Reflecting a pulsatile arterial afterload associated with diastolic dysfunction and exercise capacity, PWV may provide a clinically relevant tool to identify at-risk intermediate phenotypes (e.g. pre-HFpEF) before overt HFpEF occurs.

High-intensity interval training in patients with intermittent claudication.

OBJECTIVE: Provision, uptake, adherence, and completion rates for supervised exercise programs (SEP) for intermittent claudication (IC) are low. A shorter, more time-efficient, 6-week, high-intensity interval training (HIIT) program may be an effective alternative that is more acceptable to patients and easier to deliver. The aim of this study was to determine the feasibility of HIIT for patients with IC. METHODS: A single arm proof-of-concept study, performed in secondary care, recruiting patients with IC referred to usual-care SEPs. Supervised HIIT was performed three times per week for 6 weeks. The primary outcome was feasibility and tolerability. Potential efficacy and potential safety were considered, and an integrated qualitative study was undertaken to consider acceptability. RESULTS: A total of 280 patients were screened: 165 (59%) were eligible, and 40 (25%) were recruited. The majority (n = 31; 78%) of participants completed the HIIT program. The remaining nine patients were withdrawn or chose to withdraw. Completers attended 99% of training sessions, completed 85% of sessions in full, and performed 84% of completed intervals at the required intensity. There were no related serious adverse events. Maximum walking distance (+94 m; 95% confidence interval, 66.6-120.8 m) and the SF-36 physical component summary (+2.2; 95% confidence interval, 0.3-4.1) were improved following completion of the program. CONCLUSIONS: Uptake to HIIT was comparable to SEPs in patients with IC, but completion rates were higher. HIIT appears feasible, tolerable, and potentially safe and beneficial for patients with IC. It may provide a more readily deliverable, acceptable form of SEP. Research comparing HIIT with usual-care SEPs appears warranted.

Cardiovascular implications and physical activity in middle-aged and older adults with a history of COVID-19 (CV COVID): a protocol for a randomised controlled trial.

BACKGROUND: The clinical manifestation of COVID-19 is associated with infection and inflammation of the lungs, but there is evidence to suggest that COVID-19 may also affect the structure and function of the cardiovascular system. At present, it is not fully understood to what extent COVID-19 impacts cardiovascular function in the short- and long-term following infection. The aim of the present study is twofold: (i) to define the effect of COVID-19 on cardiovascular function (i.e. arterial stiffness, cardiac systolic and diastolic function) in otherwise healthy individuals and (ii) to evaluate the effect of a home-based physical activity intervention on cardiovascular function in people with a history of COVID-19. METHODS: This prospective, single-centre, observational study will recruit 120 COVID-19-vaccinated adult participants aged between 50 and 85 years, i.e. 80 with a history of COVID-19 and 40 healthy controls without a history of COVID-19. All participants will undergo baseline assessments including 12-lead electrocardiography, heart rate variability, arterial stiffness, rest and stress echocardiography with speckle tracking imaging, spirometry, maximal cardiopulmonary exercise testing, 7-day physical activity and sleep measures and quality of life questionnaires. Blood samples will be collected to assess the microRNA expression profiles, cardiac and inflammatory biomarkers, i.e. cardiac troponin T; N-terminal pro B-type natriuretic peptide; tumour necrosis factor alpha; interleukins 1, 6 and 10; C-reactive protein; D-dimer; and vascular endothelial growth factors. Following baseline assessments, COVID-19 participants will be randomised 1:1 into a 12-week home-based physical activity intervention aiming to increase their daily number of steps by 2000 from baseline. The primary outcome is change in left ventricular global longitudinal strain. Secondary outcomes are arterial stiffness, systolic and diastolic function of the heart, functional capacity, lung function, sleep measures, quality of life and well-being (depression, anxiety, stress and sleep efficiency). DISCUSSION: The study will provide insights into the cardiovascular implications of COVID-19 and their malleability with a home-based physical activity intervention. TRIAL REGISTRATION: ClinicalTrials.gov NCT05492552. Registered on 7 April 2022.

Capability, Opportunity, and Motivation-Identifying Constructs for Increasing Physical Activity Behaviours in Women with Polycystic Ovary Syndrome (PCOS).

Polycystic ovary syndrome (PCOS) is the commonest endocrinopathy in reproductive-aged women. Because increased adiposity is pivotal in the severity of PCOS-related symptoms, treatment usually incorporates increasing energy expenditure through physical activity (PA). This study aimed to understand the reasons why women with PCOS engage in PA/exercise, which could support the development of targeted behavioural interventions in this at-risk population. Validated questionnaires were administered for self-reported PA levels, quality of life, mental health, illness perception, sleep quality, and capability, opportunity, and motivation (COM) for PA. Using categorical PA data, outcomes were compared between groups; ordinal logistic regression (OLR) was used to identify whether COM could explain PA categorisation. A total of 333 participants were eligible; favourable differences were reported for body mass index, depression, mental wellbeing, self-rated health, illness perception, and insomnia severity for those reporting the highest PA levels. COM scores increased according to PA categorisation, whilst OLR identified conscious and automatic motivation as explaining the largest PA variance. The most active participants reported favourable data for most outcomes. However, determining whether health is protected by higher PA or ill health is a barrier to PA was not possible. These findings suggest that future behavioural interventions should be targeted at increasing patient motivation.

Remote maintenance cardiac rehabilitation (MAINTAIN): A protocol for a randomised feasibility study.

Background: Long-term adherence to exercise is often poor for people with coronary heart disease (CHD) who have completed supervised, centre-based cardiac rehabilitation. The aim of this study is to assess the feasibility of a remotely prescribed, delivered and monitored cardiac rehabilitation intervention using a wearable device to support long-term adherence to exercise and physical activity during maintenance of cardiac rehabilitation. Methods: After completing cardiac rehabilitation, 30 participants with CHD, will be randomised (1:1) to an intervention (n = 15) or a usual care group (n = 15) in a 12-month feasibility randomised controlled trial (RCT). The intervention will comprise of an exercise consultation, personalised exercise prescription delivered via a wearable activity monitor using biometric feedback, regular monitoring via check-ins, and feedback text-messages for 6-months. Participants will be assessed at baseline (following completion of cardiac rehabilitation) and at three-, six-, and 12-months post-randomisation. The primary outcome will be feasibility, including assessment of eligibility, recruitment, adherence, and acceptability. Secondary outcomes will include exercise capacity, physical activity behaviours, cardiovascular disease risk and quality of life. Semi-structured interviews will be conducted at three-, six-, and 12-months post-randomisation (and with those who drop-out) to explore the acceptability of the study intervention and procedures. A questionnaire will be offered to those who decline participation. Discussion: The MAINTAIN study will evaluate the feasibility of conducting a future definitive multi-centre RCT testing a remotely prescribed and monitored long-term mHealth maintenance exercise programme, versus usual care, for people with CHD who have completed cardiac rehabilitation. Trial registration number: ClinicalTrials.gov, NCT05292287. Registered on 22/03/2022.

High-intensity interval training in cardiac rehabilitation: a multi-centre randomized controlled trial.

BACKGROUND: There is a lack of international consensus regarding the prescription of high-intensity interval training (HIIT) for people with coronary artery disease (CAD) attending cardiac rehabilitation (CR). AIMS: To assess the clinical effectiveness and safety of low-volume HIIT compared with moderate-intensity steady-state (MISS) exercise training for people with CAD. METHODS AND RESULTS: We conducted a multi-centre RCT, recruiting 382 patients from 6 outpatient CR centres. Participants were randomized to twice-weekly HIIT (n = 187) or MISS (n = 195) for 8 weeks. HIIT consisted of 10 × 1 min intervals of vigorous exercise (>85% maximum capacity) interspersed with 1 min periods of recovery. MISS was 20-40 min of moderate-intensity continuous exercise (60-80% maximum capacity). The primary outcome was the change in cardiorespiratory fitness [peak oxygen uptake (VO2 peak)] at 8 week follow-up. Secondary outcomes included cardiovascular disease risk markers, cardiac structure and function, adverse events, and health-related quality of life. At 8 weeks, VO2peak improved more with HIIT (2.37 mL.kg-1.min-1; SD, 3.11) compared with MISS (1.32 mL.kg-1.min-1; SD, 2.66). After adjusting for age, sex, and study site, the difference between arms was 1.04 mL.kg-1.min-1 (95% CI, 0.38 to 1.69; P = 0.002). Only one serious adverse event was possibly related to HIIT. CONCLUSIONS: In stable CAD, low-volume HIIT improved cardiorespiratory fitness more than MISS by a clinically meaningful margin. Low-volume HIIT is a safe, well-tolerated, and clinically effective intervention that produces short-term improvement in cardiorespiratory fitness. It should be considered by all CR programmes as an adjunct or alternative to MISS. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02784873. https://clinicaltrials.gov/ct2/show/NCT02784873.

Cardiac rehabilitation exercise training can improve cardiorespiratory fitness and quality of life for people with coronary artery disease, but sometimes, it is not effective. The intensity of the exercise training may be important. We conducted a randomized controlled trial to test if moderate-intensity exercise or high-intensity exercise was better.High-intensity interval training was more effective than moderate-intensity exercise training for improving cardiorespiratory fitness in people with coronary artery disease attending cardiac rehabilitation.High-intensity interval training was safe and well tolerated.

Hypoxia during maintenance hemodialysis-the critical role of pH.

Background: The impact and management of subclinical hypoxia during hemodialysis is a significant medical challenge. As key determinants of O2 availability and delivery, proposed mechanisms contributing to hypoxia include ischemia, alkalemia and pulmonary leukocyte sequestration. However, no study has comprehensively investigated and compared these interrelated mechanisms throughout a typical hemodialysis treatment week. This study aimed to comprehensively assess the physiological mechanisms that contribute to hypoxia during hemodialysis. Methods: In 76 patients, we measured arterial blood gases and pH at four time-points during hemodialysis (start, 15 min, 60 min, end) over the course of a standard treatment week. For the mid-week hemodialysis session, we additionally measured central hemodynamics (non-invasive cardiac output monitoring) and white blood cell count. Results: Linear regression modelling identified changes in pH, but not central hemodynamics or white blood cell count, to be predictive of changes in PaO2 throughout hemodialysis (e.g. at 60 min, ß standardized coefficient pH = 0.45, model R2 = 0.25, P < .001). Alkalemia, hypokalemia, decreased calcium and increased hemoglobin-O2 affinity (leftward shift in the oxyhemoglobin dissociation curve) were evident at the end of hemodialysis. pH and hemoglobin-O2 affinity at the start of hemodialysis increased incrementally over the course of a standard treatment week. Conclusion: These data highlight the important role of pH in regulating O2 availability and delivery during hemodialysis. Findings support routine pH monitoring and personalized dialysate bicarbonate prescription to mitigate the significant risk of alkalemia and subclinical hypoxia.

Validity and reliability of short-term heart-rate variability from disposable electrocardiography leads.

Background and Aims: Single-use electrocardiography (ECG) leads have been developed to reduce healthcare-associated infection. This study compared the validity and reliability of short-term heart rate variability (HRV) obtained from single-use disposable ECG leads. Methods: Thirty healthy subjects (33 ± 10 years; 9 females) underwent 5-min resting HRV assessments using disposable (single use) ECG cable and wire system (Kendall DL™ Cardinal Health) and a standard, reusable ECG leads (CardioExpress, Spacelabs Healthcare). Results: Intraclass correlation coefficient (ICC) with 95% confidence interval (CI) between disposable and reusable ECG leads was for the time domain [R-R interval (ms); 0.99 (0.91, 1.00)], the root mean square of successive normal R-R interval differences (RMSSD) (ms); 0.91 (0.76, 0.96), the SD of normal-to-normal R-R intervals (SDNN) (ms); 0.91 (0.68, 0.97) and frequency domain [low-frequency (LF) normalized units (nu); 0.90 (0.79, 0.95), high frequency (HF) nu; 0.91 (0.80, 0.96), LF power (ms2); 0.89 (0.62, 0.96), HF power (ms2); 0.90 (0.72, 0.96)] variables. The mean difference and upper and lower limits of agreement between disposable and reusable leads for time- and frequency-domain variables were acceptable. Analysis of repeated measures using disposable leads demonstrated excellent reproducibility (ICC 95% CI) for R-R interval (ms); 0.93 (0.85, 0.97), RMSSD (ms); 0.93 (0.85, 0.97), SDNN (ms); 0.88 (0.75, 0.95), LF power (ms2); 0.87 (0.72, 0.94), and HF power (ms2); 0.88 (0.73, 0.94) with coefficient of variation ranging from 2.2% to 5% (p > 0.37 for all variables). Conclusion: Single-use Kendall DL™ ECG leads demonstrate a valid and reproducible tool for the assessment of HRV.

Initiation of Dialysis Is Associated With Impaired Cardiovascular Functional Capacity.

Background The transition to dialysis period carries a substantial increased cardiovascular risk in patients with chronic kidney disease. Despite this, alterations in cardiovascular functional capacity during this transition are largely unknown. The present study therefore sought to assess ventilatory exercise response measures in patients within 1 year of initiating dialysis. Methods and Results We conducted a cross-sectional study of 241 patients with chronic kidney disease stage 5 from the CAPER (Cardiopulmonary Exercise Testing in Renal Failure) study and from the intradialytic low-frequency electrical muscle stimulation pilot randomized controlled trial cohorts. Patients underwent cardiopulmonary exercise testing and echocardiography. Of the 241 patients (age, 48.9 [15.0] years; 154 [63.9%] men), 42 were predialytic (mean estimated glomerular filtration rate, 14 mL·min-1·1.73 m-2), 54 had a dialysis vintage ≤12 months, and 145 had a dialysis vintage >12 months. Dialysis vintage ≤12 months exhibited a significantly impaired cardiovascular functional capacity, as assessed by oxygen uptake at peak exercise (18.7 [5.8] mL·min-1·kg-1) compared with predialysis (22.7 [5.2] mL·min-1·kg-1; P<0.001). Dialysis vintage ≤12 months also exhibited reduced peak workload, impaired peak heart rate, reduced circulatory power, and increased left ventricular mass index (P<0.05 for all) compared with predialysis. After excluding those with prior kidney transplant, dialysis vintage >12 months exhibited a lower oxygen uptake at peak exercise (17.0 [4.9] mL·min-1·kg-1) compared with dialysis vintage ≤12 months (18.9 [5.9] mL·min-1·kg-1; P=0.033). Conclusions Initiating dialysis is associated with a significant impairment in oxygen uptake at peak exercise and overall decrements in ventilatory and hemodynamic exercise responses that predispose patients to functional dependence. The magnitude of these changes is comparable to the differences between low-risk New York Heart Association class I and higher-risk New York Heart Association class II to IV heart failure.